“”I confess, without shame, that I am sick and tired of fighting — its glory is all moonshine; even success the most brilliant is over dead and mangled bodies, with the anguish and lamentations of distant families, appealing to me for sons, husbands, and fathers … it is only those who have never heard a shot, never heard the shriek and groans of the wounded and lacerated … that cry aloud for more blood, more vengeance, more desolation.

Throughout history, whenever a dispute could not be settled peacefully, or leaders/governments of nations in conflict just didn't feel like doing so, or when leaders just got bored and felt like playing a real life version of Diplomacy, violence broke out. When enough people were on each side of the violence, it is called a war. Many efforts have been made to either prevent all wars[2] or to mitigate the effects of war.[3] They still occur frequently, although most of the violence has nowadays shifted to the sub-state level.

A war is a large-scale conflict between two or more groups in which each group is attempting to achieve a political goal of some kind through the employment of violence, often with the goal of the winner forcing the loser to the bargaining table to agree to terms favorable to them. However, the exact scale of deaths needed to call something a war is constantly under debate. There are several broad types of wars, which can be divided and subdivided to your heart's content.

Since the rise of the concept of the nation-state, wars have traditionally been fought between the armed forces of two or more sovereign states. While irregulars and guerrillas may play a part in such wars, the states are the ones in control.[5] Such wars are, at least in principle, governed by international law (most notably the Geneva Conventions), and explicitly discouraged by institutions such as the UN, which had its member nations renounce war as a method of solving disputes: politics being what it is, this just meant they stopped declaring war on each other, with the US' last declaration of war having been in 1942.

Wars of aggression are fought without the justification of self-defense. Since they are often fought over controlling land, they are also known as "wars of conquest," although they needn't be fought over certain territories: in ancient times, invasions were often more about pillage than empire-building. Wars of aggression are seen as one of the, if not the, largest crimes against humanity.[6]

A civil war describes a situation in which factions within one nation fight for control. This covers armed insurrections against the government, as well as organized violence between groups that the state is unable to stop. In both cases, civil wars can turn into international conflicts when outside powers are prompted to intervene, and in such cases often become proxy wars (see below) between those external parties. Civil wars are often extremely bloody affairs, because they blur the line between soldiers and civilians. Sometimes, one or more of the factions involved also wage all-out campaigns of genocide or ethnic cleansing, in which civilians become targets rather than "collateral damage."

Wars of revolution are also usually confined to a single country's territory. Their purpose is to overthrow the existing government structure and replace it with something the revolutionaries think will better serve the people. There are basically two kinds — in one, usually called a war of independence, a country or territory seeks to liberate itself from a colonial or imperial power; in the other, the goal is to overthrow the country's existing independent government. Examples of the former include the American War of Independence against England, and the Algerian one against France. The latter include the French, Russian, and Cuban revolutions. As with most wars, the "legitimacy" of the revolutionaries is definitely in the eye of the beholder — one man's freedom fighter is another man's terrorist.

“”God's always on your side in a war. There's never been a war, as far as I know, when halfway through a general has said to his men: "Men – last night, in this, our hour of need, I prayed to God. Uh, unfortunately, it seems he's backing the Turks on this one..."

Religious wars are usually civil wars, though they can also be international. A religious war is one where the primary motivation behind the war is specifically religious. The most well-known religious wars were those between the European states and the Islamic empire during the Crusades, or between the Protestant and Catholics sections of Germany during the 30 Years' War. By casualties, the Taiping Rebellion was the largest religious war. Until the 21st century, it seemed that religious wars were on the decline, but many see current US actions against Iraq and Afghanistan in that light.

Proxy wars, which became more common during the Cold War, are typically local civil wars or wars between smaller nations in which major powers are backing one or more of the combative factions to further their own ends, but do not wish to dirty their hands with each others' blood directly. The Arab-Israeli conflict used to be cast in this light during the 1960s and 70s, and Soviet support for North Vietnam or American support for the mujahideen in Afghanistan are also prominent examples. Both of the latter cases are examples where one side was fighting a proxy war, while its primary opponent was engaged directly. A proxy war carries a number of benefits:

Someone else is providing a significant portion of the armed forces, thus lessening casualties for the external parties. In some cases interested parties may supply material support and training while refraining from providing combat personnel, such as the case of America's support for the mujahideen in their efforts to counter the Soviet invasion of Afghanistan.

An increased sphere of influence - should the war be a successful one.

A large-scale war between major powers is likely to breed the danger of escalation, including the threat of nuclear war.

Fighting in one's own country tends to leave things in a bit of a mess, so it's preferable to have the fighting take place elsewhere.

However, relying on proxies can also be very messy, since they're not really under your control. They often do things you'd rather they didn't (like kill innocent people, start more wars at inopportune times, or turn around and attack you instead). It is also very easy for a conflict to start as a proxy war, only to eventually draw the patron in as well. The US involvement in Vietnam, for example, began with providing training and materiel for the South Vietnamese, but eventually escalated into a massive troop deployment and saw the US turn into the major combatant. The Syrian Civil War is in part a proxy war, with the US backing the Opposition and Russia backing Assad, both of which are pretty bad, leaving the Syrian Democratic Forces, or the ONLY good side in this, to for the most part single-handedly fight the psychotic beheading lunatics, due to the two major powers' little pissing contest making them too busy to help, and it's actually going quite well.

Guerrilla warfare is a combat situation when one of the combatants is a large organized army, and the other side is made of small, often independent units that aggressively attack any way they can, including ambushes and raids.

"Sometimes I think war is God's way of teaching us geography."Paul Rodriguez

In today's globalized world, some wars are starting to cross-over between types, where fighters from different states come together in undeclared wars and civil wars spill out past national boundaries. This can be seen most clearly in the proxy struggles between the Soviet Union and Afghanistan in the 1980s, and now in the fighting in Sudan/Chad/etc.

The term gang War is applied to ongoing, long term conflicts between two or more gangs fighting for control of territory. It has all the characteristics of a traditional war, except the parties do not represent nations or states. Gang wars more closely represent guerrilla war in style.

Modern US media has used the term "war" to define aggressive moves by the government, or by various groups of people to end some seemingly unwanted problem in society. We used to have the War on Poverty, but it was replaced by the the War on Drugs and the non-existent War on Christmas, among others. The War on Drugs has led to increased rates of drug abuse. All it has really done is fill up private prisons with people convicted of non-violent offenses who become violent offenders when they are released and ostracized for being convicts.

War is also a card game of pure chance, typically played with one ordinary deck and two players, but extendable to more decks or players. Cards are dealt out face-down to each player, giving each player their own deck. Players cannot look at their deck or anyone else's. In a round, every player flips over the top card of their deck. Whoever has the card with the highest value[8] gets all cards played in that round, to put at the bottom of their deck. If two or more players are tied for the highest-valued card, then a "war" occurs. Each player involved in the tie puts down three cards face-down, and flips over another card, which is compared instead. If one of the cards' values is greater than the other, then that player gets all cards involved in the "war." Otherwise, the war proceeds as before until a resolution is determined. When a player runs out of cards in their deck, they are out of the game. Rounds proceed as described until everybody except for one player has been eliminated. The remaining player is the winner.